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<head><meta charset="utf-8"><title>design meeting 2020.03.24 · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html">design meeting 2020.03.24</a></h3>

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<a name="191663614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191663614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191663614">(Mar 24 2020 at 19:53)</a>:</h4>
<p>Hi <span class="user-group-mention" data-user-group-id="692">@WG-traits</span> <span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span></p>



<a name="191663625"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191663625" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191663625">(Mar 24 2020 at 19:53)</a>:</h4>
<p>~7 minutes to meeting</p>



<a name="191663695"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191663695" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191663695">(Mar 24 2020 at 19:54)</a>:</h4>
<p>Announcement: Today ends the first sprint of 2020 :)</p>



<a name="191663730"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191663730" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191663730">(Mar 24 2020 at 19:54)</a>:</h4>
<p>Link to Hackmd of meeting agenda/planning: <a href="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both" target="_blank" title="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both">https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both</a></p>



<a name="191664457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664457">(Mar 24 2020 at 20:00)</a>:</h4>
<p>here</p>



<a name="191664596"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664596" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664596">(Mar 24 2020 at 20:01)</a>:</h4>
<p>Okay, <span class="user-group-mention" data-user-group-id="692">@WG-traits</span> meeting time :)</p>



<a name="191664778"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664778" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664778">(Mar 24 2020 at 20:03)</a>:</h4>
<p>Ah there you are niko</p>



<a name="191664818"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664818" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664818">(Mar 24 2020 at 20:03)</a>:</h4>
<p>Forgot to <span aria-label="wave" class="emoji emoji-1f44b" role="img" title="wave">:wave:</span></p>



<a name="191664829"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664829" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664829">(Mar 24 2020 at 20:03)</a>:</h4>
<p>I'm skimming over the agenda</p>



<a name="191664883"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664883" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664883">(Mar 24 2020 at 20:04)</a>:</h4>
<p>Anyways, so since today is the last day of the sprint, I figured we should start by going over what we accomplished?</p>



<a name="191664891"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664891" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664891">(Mar 24 2020 at 20:04)</a>:</h4>
<p>Great idea :)</p>



<a name="191664899"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664899" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664899">(Mar 24 2020 at 20:04)</a>:</h4>
<p>It feels like we did a lot</p>



<a name="191664905"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664905" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664905">(Mar 24 2020 at 20:04)</a>:</h4>
<p>So let's see: (feel free to start listing things)</p>



<a name="191664910"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664910" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664910">(Mar 24 2020 at 20:04)</a>:</h4>
<p>Yes, we did</p>



<a name="191664921"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664921" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664921">(Mar 24 2020 at 20:04)</a>:</h4>
<p>Looking over the <a href="https://rust-lang.github.io/wg-traits/roadmap/skill-tree.html" target="_blank" title="https://rust-lang.github.io/wg-traits/roadmap/skill-tree.html">skill tree</a></p>



<a name="191664932"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664932" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664932">(Mar 24 2020 at 20:04)</a>:</h4>
<p>Things that <em>I</em> did:</p>



<a name="191664933"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664933" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664933">(Mar 24 2020 at 20:04)</a>:</h4>
<ul>
<li>Added <code>&amp;self</code> to intern methods (<span class="user-mention" data-user-id="220273">@Jane Lusby</span>)</li>
</ul>



<a name="191664944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664944">(Mar 24 2020 at 20:04)</a>:</h4>
<ul>
<li>Added <code>&amp;self</code> to data methods (<span class="user-mention" data-user-id="220273">@Jane Lusby</span>, <span class="user-mention" data-user-id="116458">@Charles Lew</span>)</li>
</ul>



<a name="191664991"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191664991" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191664991">(Mar 24 2020 at 20:05)</a>:</h4>
<ul>
<li>Progress towards adapt rustc to debruijn model (<span class="user-mention" data-user-id="116009">@nikomatsakis</span>)</li>
</ul>



<a name="191665020"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665020" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665020">(Mar 24 2020 at 20:05)</a>:</h4>
<ul>
<li>Prototype and evaluation underway for recursive solver (<span class="user-mention" data-user-id="129457">@Florian Diebold</span>)</li>
</ul>



<a name="191665032"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665032" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665032">(Mar 24 2020 at 20:05)</a>:</h4>
<ul>
<li>Initial PR towards impl trait (<span class="user-mention" data-user-id="125131">@detrumi</span>), pending some improvements</li>
</ul>



<a name="191665120"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665120" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665120">(Mar 24 2020 at 20:06)</a>:</h4>
<ul>
<li>Exploratory rustc-chalk integration MVP (<span class="user-mention" data-user-id="232957">@Jack Huey</span>)</li>
</ul>



<a name="191665122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665122">(Mar 24 2020 at 20:06)</a>:</h4>
<ul>
<li>A bit of work to make chalk-engine more <code>UnwindSafe</code></li>
<li>Removed <code>lalrpop-intern</code>as a default dependency of <code>chalk-ir</code></li>
<li>Initial work in Chalk to get it to build in rustc</li>
</ul>



<a name="191665141"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665141" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665141">(Mar 24 2020 at 20:07)</a>:</h4>
<p>Not sure what the status of the tracing work is</p>



<a name="191665160"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665160" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665160">(Mar 24 2020 at 20:07)</a>:</h4>
<ul>
<li>Lots of work on the book :)</li>
</ul>



<a name="191665183"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665183" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665183">(Mar 24 2020 at 20:07)</a>:</h4>
<p><span class="user-mention" data-user-id="198819">@David Barsky</span></p>



<a name="191665193"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665193" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665193">(Mar 24 2020 at 20:07)</a>:</h4>
<p>tracing seems to be somewhat working</p>



<a name="191665217"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665217" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665217">(Mar 24 2020 at 20:07)</a>:</h4>
<p>see screenshot here: <a href="#narrow/stream/144729-wg-traits/topic/tracing.20in.20chalk/near/190618258" title="#narrow/stream/144729-wg-traits/topic/tracing.20in.20chalk/near/190618258">https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/tracing.20in.20chalk/near/190618258</a></p>



<a name="191665268"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665268" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665268">(Mar 24 2020 at 20:08)</a>:</h4>
<p>side note that I was trying to develop chalk on my windows machine using VSCode, and one of the main obstacles I encountered was that powershell doesn't make it easy to set env variables :) not sure if tracing helps at all there, I guess prob not</p>



<a name="191665354"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665354" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665354">(Mar 24 2020 at 20:09)</a>:</h4>
<p>interesting</p>



<a name="191665384"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665384" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665384">(Mar 24 2020 at 20:09)</a>:</h4>
<p>I just use wsl</p>



<a name="191665421"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665421" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665421">(Mar 24 2020 at 20:09)</a>:</h4>
<p>I went back to emacs and wsl for now</p>



<a name="191665496"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665496" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665496">(Mar 24 2020 at 20:10)</a>:</h4>
<p>So, yes, we did a lot this sprint</p>



<a name="191665504"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665504" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665504">(Mar 24 2020 at 20:10)</a>:</h4>
<p>good job everyone :)</p>



<a name="191665605"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665605" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665605">(Mar 24 2020 at 20:11)</a>:</h4>
<p>So, I think we agreed last week that we should write a blog post to go out sometime this week</p>



<a name="191665612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665612">(Mar 24 2020 at 20:11)</a>:</h4>
<p>then start the next sprint next week</p>



<a name="191665617"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665617" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665617">(Mar 24 2020 at 20:11)</a>:</h4>
<p>tracing can set filters without using env variables</p>



<a name="191665683"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665683" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665683">(Mar 24 2020 at 20:12)</a>:</h4>
<p>i mean you still need to pick a way to do inputs but its not hard to avoid that specific hurdle</p>



<a name="191665696"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665696" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665696">(Mar 24 2020 at 20:12)</a>:</h4>
<p>the main problem is that we have to get the info from <code>x.py test</code> down</p>



<a name="191665706"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665706" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665706">(Mar 24 2020 at 20:12)</a>:</h4>
<p>s/to do inputs/to provide input/</p>



<a name="191665707"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665707" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665707">(Mar 24 2020 at 20:12)</a>:</h4>
<p>anyway, not imp't :)</p>



<a name="191665729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665729">(Mar 24 2020 at 20:12)</a>:</h4>
<p>secretly I'm glad for an excuse to go back to emacs, though vscode is nice</p>



<a name="191665730"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665730" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665730">(Mar 24 2020 at 20:12)</a>:</h4>
<p>mk</p>



<a name="191665745"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665745" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665745">(Mar 24 2020 at 20:12)</a>:</h4>
<p>lol</p>



<a name="191665761"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665761" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665761">(Mar 24 2020 at 20:12)</a>:</h4>
<p>you can use vscode remote with wsl</p>



<a name="191665767"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665767" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665767">(Mar 24 2020 at 20:12)</a>:</h4>
<p>works really well tbh</p>



<a name="191665769"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665769" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> David Barsky <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665769">(Mar 24 2020 at 20:12)</a>:</h4>
<p>re: tracing—I might need to work with jane (or anyone!) to get some semantically meaningful data out. I feel like what i have is much too noisy, and I have difficulty saying <em>what</em> should be emitted.</p>



<a name="191665788"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665788" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665788">(Mar 24 2020 at 20:13)</a>:</h4>
<p>(or just vscode with wsl terminal)</p>



<a name="191665795"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665795" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665795">(Mar 24 2020 at 20:13)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191665605" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191665605">said</a>:</p>
<blockquote>
<p>So, I think we agreed last week that we should write a blog post to go out sometime this week</p>
</blockquote>
<p>that seems ideal -- I guess it would highlight the work that was done and talk about our upcoming goals</p>



<a name="191665833"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665833" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665833">(Mar 24 2020 at 20:13)</a>:</h4>
<p>there were also a few folks who jumped in recently saying they were interested in helping out</p>



<a name="191665848"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665848" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665848">(Mar 24 2020 at 20:13)</a>:</h4>
<p>Do you want to write that? (At least the initial draft) or do you want me to</p>



<a name="191665864"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665864" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665864">(Mar 24 2020 at 20:13)</a>:</h4>
<p>Oh yeah, lots of interest</p>



<a name="191665917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665917">(Mar 24 2020 at 20:14)</a>:</h4>
<p>Either way is ok, I think I could bang something out, I'm more interested in discussing <em>now</em> what those goals should be</p>



<a name="191665937"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665937" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665937">(Mar 24 2020 at 20:14)</a>:</h4>
<p>Speaking of which, someone should respond to <a href="https://github.com/rust-lang/chalk/issues/333" target="_blank" title="https://github.com/rust-lang/chalk/issues/333">https://github.com/rust-lang/chalk/issues/333</a></p>



<a name="191665985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665985">(Mar 24 2020 at 20:14)</a>:</h4>
<p>ah, I just came up with "yet another" place I sort of wanted that</p>



<a name="191665994"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191665994" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191665994">(Mar 24 2020 at 20:15)</a>:</h4>
<p>Right, so I just started listing some things that came to mind in the hackmd doc</p>



<a name="191666046"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666046" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666046">(Mar 24 2020 at 20:15)</a>:</h4>
<blockquote>
<div class="codehilite"><pre><span></span>   * Rustc ty refactor/librarification
        * the design 
        * Proposed path is to start by adjusting the `Ty` API, e.g., changing `ty.kind` to `ty.kind(tcx)`.
        * Compare names of things in rustc 
        * Might be simple enough to start moving some things from `rustc::ty` to a separate in-tree crate, as-is
            * `Ty`, `TypeFolder`, `TypeVisitor`
    * rustc `Predicate` refactor?
        * Niko - post a short description
    * Rustc integration
        * &quot;MVP&quot;?
        * Builtin traits
        * Fn and closures
        * Refactoring debruijn indices
            * There is ongoing work on the chalk side
            * And [some changes on the rustc side](https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/debruijn.20indices.20and.20bound.20variables.20chalk.23334/near/191636362)
        * Params?
    * Performance? (very open-ended)
        * Benchmarks
        * Tracing
        * Memory usage
        * Creating a .chalk from a given program for reproducing
</pre></div>


</blockquote>



<a name="191666170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666170">(Mar 24 2020 at 20:16)</a>:</h4>
<p>Also some of these: <a href="https://paper.dropbox.com/doc/wg-traits-2020-sprint-planning--AwyHYhIF7xYmKXYdUxYJaEk4Ag-SSt74TfcovdnKKhZNyzeW" target="_blank" title="https://paper.dropbox.com/doc/wg-traits-2020-sprint-planning--AwyHYhIF7xYmKXYdUxYJaEk4Ag-SSt74TfcovdnKKhZNyzeW">https://paper.dropbox.com/doc/wg-traits-2020-sprint-planning--AwyHYhIF7xYmKXYdUxYJaEk4Ag-SSt74TfcovdnKKhZNyzeW</a></p>



<a name="191666178"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666178" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666178">(Mar 24 2020 at 20:16)</a>:</h4>
<p>might still be relevant</p>



<a name="191666255"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666255" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666255">(Mar 24 2020 at 20:17)</a>:</h4>
<p>so</p>



<a name="191666364"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666364" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666364">(Mar 24 2020 at 20:18)</a>:</h4>
<p>I think working towards the rustc integration MVP is a good "meta goal" -- I am also somewhat motivated by the work to extract a rustc type library, I think that those kind of overlap in some cases</p>



<a name="191666424"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666424" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666424">(Mar 24 2020 at 20:18)</a>:</h4>
<p>for rustc MVP integration purposes, I am imagining that we want to basically "spike" through to get some very simple tests working</p>



<a name="191666434"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666434" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666434">(Mar 24 2020 at 20:18)</a>:</h4>
<p>e.g.</p>



<a name="191666453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666453">(Mar 24 2020 at 20:19)</a>:</h4>
<p>I actually don't think they overlap, in practice</p>



<a name="191666474"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666474" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666474">(Mar 24 2020 at 20:19)</a>:</h4>
<div class="codehilite"><pre><span></span><span class="k">struct</span> <span class="nc">Foo</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="k">trait</span><span class="w"> </span><span class="n">Bar</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="k">impl</span><span class="w"> </span><span class="n">Foo</span><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="n">Bar</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="k">fn</span> <span class="nf">generic</span><span class="o">&lt;</span><span class="n">T</span>: <span class="nc">Bar</span><span class="o">&gt;</span><span class="p">(</span><span class="n">t</span>: <span class="nc">T</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="p">}</span><span class="w"></span>
<span class="k">fn</span> <span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"></span>
<span class="w">    </span><span class="n">generic</span>::<span class="o">&lt;</span><span class="n">Foo</span><span class="o">&gt;</span><span class="p">();</span><span class="w"></span>
<span class="p">}</span><span class="w"></span>
</pre></div>



<a name="191666491"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666491" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666491">(Mar 24 2020 at 20:19)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191666453" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191666453">said</a>:</p>
<blockquote>
<p>I actually don't think they overlap, in practice</p>
</blockquote>
<p>the debruijn work, at least, seems to me to overlap</p>



<a name="191666499"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666499" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666499">(Mar 24 2020 at 20:19)</a>:</h4>
<p>(also, in my branch a couple of the -Z chalk tests do pass)</p>



<a name="191666507"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666507" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666507">(Mar 24 2020 at 20:19)</a>:</h4>
<p>although, maybe not</p>



<a name="191666569"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666569" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666569">(Mar 24 2020 at 20:20)</a>:</h4>
<p>Well, I guess intially they don't really overlap</p>



<a name="191666581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666581">(Mar 24 2020 at 20:20)</a>:</h4>
<p>Of course, later on they will</p>



<a name="191666583"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666583" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666583">(Mar 24 2020 at 20:20)</a>:</h4>
<p>(that is, if we eagerly convert <code>Ty</code> to <code>&amp;TyData</code>, as we talked about earlier, the debruijn work isn't really a dependency)</p>



<a name="191666622"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666622" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666622">(Mar 24 2020 at 20:20)</a>:</h4>
<p>since you can convert the rustc style types to chalk style</p>



<a name="191666634"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666634" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666634">(Mar 24 2020 at 20:20)</a>:</h4>
<p>without changing the chalk side</p>



<a name="191666637"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666637" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666637">(Mar 24 2020 at 20:20)</a>:</h4>
<p>But I was sort of thinking that the initial step would be to extract out the pieces that <em>would go</em> into the library out first</p>



<a name="191666698"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666698" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666698">(Mar 24 2020 at 20:21)</a>:</h4>
<p>even if what that library looks like is very different right now</p>



<a name="191666714"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666714" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666714">(Mar 24 2020 at 20:21)</a>:</h4>
<p>do you mean in rustc?</p>



<a name="191666716"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666716" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666716">(Mar 24 2020 at 20:21)</a>:</h4>
<p>I'm not sure I'd start there</p>



<a name="191666717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666717">(Mar 24 2020 at 20:21)</a>:</h4>
<p>then bit-by-bit, we can refactor</p>



<a name="191666721"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666721" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666721">(Mar 24 2020 at 20:21)</a>:</h4>
<p>yes</p>



<a name="191666743"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666743" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666743">(Mar 24 2020 at 20:21)</a>:</h4>
<p>oh</p>



<a name="191666756"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666756" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666756">(Mar 24 2020 at 20:21)</a>:</h4>
<p>I'm debating :)</p>



<a name="191666760"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666760" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666760">(Mar 24 2020 at 20:21)</a>:</h4>
<p>the reason is</p>



<a name="191666785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666785">(Mar 24 2020 at 20:21)</a>:</h4>
<p>right now, I think a lot of the definitions are quite tied to <code>tcx</code> and there's no convenient way to separate that out</p>



<a name="191666831"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666831" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666831">(Mar 24 2020 at 20:22)</a>:</h4>
<p>at least for inherent methods</p>



<a name="191666898"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666898" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666898">(Mar 24 2020 at 20:22)</a>:</h4>
<p>so if we were going to create a library, it would either have to use more extension traits to add methods, or else include the arena code from rustc</p>



<a name="191666921"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666921" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666921">(Mar 24 2020 at 20:22)</a>:</h4>
<p>and I don't think we'd want that code in the end</p>



<a name="191666946"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666946" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666946">(Mar 24 2020 at 20:23)</a>:</h4>
<p>I think it might be better to start by trying to factor the types a bit so that they can be made generic in a transparent way, but I'm not 100% sure</p>



<a name="191666968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191666968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191666968">(Mar 24 2020 at 20:23)</a>:</h4>
<p>some of that factoring is fairly rote anyway and needs to happen one way or the other</p>



<a name="191667000"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667000" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667000">(Mar 24 2020 at 20:23)</a>:</h4>
<p>but I do think it'd be a good use of time to start to elaborate the types that <em>would</em> be in there</p>



<a name="191667008"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667008" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667008">(Mar 24 2020 at 20:23)</a>:</h4>
<p>or <em>should</em></p>



<a name="191667036"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667036" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667036">(Mar 24 2020 at 20:23)</a>:</h4>
<p>and maybe it is a good use of time to try extacting them, just to get an idea what goes wrong</p>



<a name="191667052"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667052" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667052">(Mar 24 2020 at 20:23)</a>:</h4>
<p>(i.e., if you pull out this type, you need to pull out that type too, etc)</p>



<a name="191667054"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667054" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667054">(Mar 24 2020 at 20:23)</a>:</h4>
<p>I think this is probably going to come down to trying it out</p>



<a name="191667105"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667105" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667105">(Mar 24 2020 at 20:24)</a>:</h4>
<p>end of the day there is lots of things to attack</p>



<a name="191667112"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667112" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667112">(Mar 24 2020 at 20:24)</a>:</h4>
<p>exactly</p>



<a name="191667114"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667114" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667114">(Mar 24 2020 at 20:24)</a>:</h4>
<p>but I agree it's not blocking MVP integration "per se"</p>



<a name="191667142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667142">(Mar 24 2020 at 20:24)</a>:</h4>
<p>so what do you think <em>is</em> blocking that?</p>



<a name="191667158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667158">(Mar 24 2020 at 20:24)</a>:</h4>
<p>we talked about "builtin traits"</p>



<a name="191667175"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667175" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667175">(Mar 24 2020 at 20:24)</a>:</h4>
<p>I think just that</p>



<a name="191667185"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667185" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667185">(Mar 24 2020 at 20:24)</a>:</h4>
<p>oh</p>



<a name="191667188"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667188" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667188">(Mar 24 2020 at 20:24)</a>:</h4>
<p>which also seems like something that could be parallelized -- <span class="user-mention" data-user-id="220273">@Jane Lusby</span> was maybe going to do some of the foundational work, right?</p>



<a name="191667189"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667189" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667189">(Mar 24 2020 at 20:24)</a>:</h4>
<p>well</p>



<a name="191667203"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667203" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667203">(Mar 24 2020 at 20:25)</a>:</h4>
<blockquote>
<ul>
<li>rustc integration: <code>TypeOutlives</code>, <code>RegionOutlives</code>, <code>Subtype</code><br>
    * <code>*Outlives</code> are <code>WhereClause</code> variants, <code>Subtype</code> is <code>GoalKind</code></li>
</ul>
</blockquote>



<a name="191667226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667226">(Mar 24 2020 at 20:25)</a>:</h4>
<p>this is something we need to talk about</p>



<a name="191667238"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667238" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667238">(Mar 24 2020 at 20:25)</a>:</h4>
<p>if not here, in the other thread</p>



<a name="191667369"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667369" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667369">(Mar 24 2020 at 20:26)</a>:</h4>
<p>but other than builtin traits and that, I think the big thing is just actually writing the <em>correct</em> code to convert rustc types to chalk and back</p>



<a name="191667375"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667375" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667375">(Mar 24 2020 at 20:26)</a>:</h4>
<p>ah ok so we need to figure out the "region integration" story a bit more, yes, hmm. I have thoughts but I have to sort them out a bit maybe. Still, I feel like this is also an area where wec an probably start by cutting some horrible corners :)</p>



<a name="191667474"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667474" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667474">(Mar 24 2020 at 20:27)</a>:</h4>
<p>well not sure how necessary that is. "type outlives" is an  interesting case.</p>



<a name="191667492"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667492" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667492">(Mar 24 2020 at 20:27)</a>:</h4>
<p>that said, most of that stuff today</p>



<a name="191667501"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667501" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667501">(Mar 24 2020 at 20:27)</a>:</h4>
<p>is not handled by the "trait system" in rustc</p>



<a name="191667505"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667505" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667505">(Mar 24 2020 at 20:27)</a>:</h4>
<p>it is handled externally</p>



<a name="191667510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667510">(Mar 24 2020 at 20:27)</a>:</h4>
<p>So, the way I'm working around this currently is essentially lowering a <code>ty::Predicate</code> to an <code>Option&lt;QuantifiedWhereClause&gt;</code></p>



<a name="191667512"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667512" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667512">(Mar 24 2020 at 20:27)</a>:</h4>
<p>and I imagine we can preserve that</p>



<a name="191667538"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667538" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667538">(Mar 24 2020 at 20:27)</a>:</h4>
<p>or <code>GoalData</code></p>



<a name="191667609"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667609" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667609">(Mar 24 2020 at 20:28)</a>:</h4>
<p>basically, sort of hacking around this</p>



<a name="191667709"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667709" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667709">(Mar 24 2020 at 20:28)</a>:</h4>
<p>yeah, so, let's discuss in a bit more detail later, but I guess it suffices for now that "outlives integration" is a bullet</p>



<a name="191667786"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667786" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667786">(Mar 24 2020 at 20:29)</a>:</h4>
<p>yes</p>



<a name="191667789"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667789" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667789">(Mar 24 2020 at 20:29)</a>:</h4>
<p>what I'll say real briefly is that what rustc does <em>today</em> (which isn't <em>quite</em> what I think chalk wants to do long term) is to basically pass those outlives obligations out; this is what chalk calls "region constraints" today. We could generalize that notion</p>



<a name="191667812"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667812" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667812">(Mar 24 2020 at 20:29)</a>:</h4>
<p>So basically the answer you get back would include some region cosntraints</p>



<a name="191667829"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667829" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667829">(Mar 24 2020 at 20:29)</a>:</h4>
<p>the challenge here is that we'll have to translate those types <em>back</em> to rustc types</p>



<a name="191667894"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667894" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667894">(Mar 24 2020 at 20:30)</a>:</h4>
<p>hmm</p>



<a name="191667917"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191667917" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191667917">(Mar 24 2020 at 20:30)</a>:</h4>
<p>I think we could kind of "ignore" those region constraints for now, which means we'd be unsound with respect to borrowck, but doesn't interfere with the more interesting things we want to explore</p>



<a name="191668013"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668013" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668013">(Mar 24 2020 at 20:31)</a>:</h4>
<p>That's what I'm doing</p>



<a name="191668020"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668020" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668020">(Mar 24 2020 at 20:31)</a>:</h4>
<p>And longer term I have some thoughts on how chalk should handle things that I talked about with <span class="user-mention silent" data-user-id="116118">Matthew Jasper</span> some time back, I'll have to find the topic</p>



<a name="191668050"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668050" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668050">(Mar 24 2020 at 20:31)</a>:</h4>
<p>I guess just the question is <em>how</em> to ignore that</p>



<a name="191668075"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668075">(Mar 24 2020 at 20:31)</a>:</h4>
<p>But it may at least mean that "aligning" chalk with rustc types is sort of a "semi blocker" on doing that stuff right</p>



<a name="191668145"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668145" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668145">(Mar 24 2020 at 20:31)</a>:</h4>
<p>i.e. to lower <code>DomainGoal</code> to <code>chalk_ir::DomainGoal</code> for those, we really need an "always true" DomainGoal</p>



<a name="191668275"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668275" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668275">(Mar 24 2020 at 20:32)</a>:</h4>
<p><code>GoalData::All</code></p>



<a name="191668276"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668276" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668276">(Mar 24 2020 at 20:32)</a>:</h4>
<p>with an empty vector</p>



<a name="191668282"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668282" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668282">(Mar 24 2020 at 20:32)</a>:</h4>
<p>is always true :)</p>



<a name="191668308"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668308" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668308">(Mar 24 2020 at 20:33)</a>:</h4>
<p>I do that when I lower to <code>GoalData</code></p>



<a name="191668329"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668329" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668329">(Mar 24 2020 at 20:33)</a>:</h4>
<p>oh oh</p>



<a name="191668330"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668330" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668330">(Mar 24 2020 at 20:33)</a>:</h4>
<p>but trying to lower to <code>DomainGoal</code></p>



<a name="191668331"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668331" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668331">(Mar 24 2020 at 20:33)</a>:</h4>
<p>I see</p>



<a name="191668352"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668352" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668352">(Mar 24 2020 at 20:33)</a>:</h4>
<p>so guess I have to move it up a bit</p>



<a name="191668582"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668582" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668582">(Mar 24 2020 at 20:34)</a>:</h4>
<p>anyways, with the go-ahead to just ignore those for now, I'll figure it out :)</p>



<a name="191668608"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668608" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668608">(Mar 24 2020 at 20:35)</a>:</h4>
<p>(and we can discuss in the separate thread if needed)</p>



<a name="191668632"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668632" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668632">(Mar 24 2020 at 20:35)</a>:</h4>
<p>lets go back to things to do for next sprint</p>



<a name="191668650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668650">(Mar 24 2020 at 20:35)</a>:</h4>
<p>since that seems more important</p>



<a name="191668796"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668796" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668796">(Mar 24 2020 at 20:36)</a>:</h4>
<p>agreed</p>



<a name="191668814"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668814" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668814">(Mar 24 2020 at 20:36)</a>:</h4>
<p>although I think this is relevant</p>



<a name="191668831"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668831" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668831">(Mar 24 2020 at 20:36)</a>:</h4>
<p>yes, definitely relevant</p>



<a name="191668857"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668857" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668857">(Mar 24 2020 at 20:36)</a>:</h4>
<p>so, looking at <a href="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both" target="_blank" title="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?both">the hackmd</a>...</p>



<a name="191668913"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668913" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668913">(Mar 24 2020 at 20:37)</a>:</h4>
<p>maybe we can add a bit more details</p>



<a name="191668982"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191668982" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191668982">(Mar 24 2020 at 20:37)</a>:</h4>
<p>you're saying that some basic tests work with existing branch you have?</p>



<a name="191669054"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669054" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669054">(Mar 24 2020 at 20:38)</a>:</h4>
<p>yes</p>



<a name="191669121"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669121" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669121">(Mar 24 2020 at 20:38)</a>:</h4>
<div class="codehilite"><pre><span></span>// check-pass
// compile-flags: -Z chalk

trait Foo {}

struct Bar {}

impl Foo for Bar {}

fn main() -&gt; () {
    let _ = Bar {};
}
</pre></div>


<p>passes</p>



<a name="191669172"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669172" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669172">(Mar 24 2020 at 20:39)</a>:</h4>
<p>ok :)</p>



<a name="191669181"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669181" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669181">(Mar 24 2020 at 20:39)</a>:</h4>
<p>I've more or less been going through the tests that are there right now and seeing what doesn't work and trying to work through them</p>



<a name="191669372"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669372" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669372">(Mar 24 2020 at 20:40)</a>:</h4>
<p>I'm putting some notes about the meaning of "MVP"</p>



<a name="191669390"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669390" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669390">(Mar 24 2020 at 20:41)</a>:</h4>
<ul>
<li>rustc types are converted to chalk types deeply and eagerly</li>
<li>region integration is basically ignored, so not sound</li>
<li>chalk is responsible for generating builtin trait rules, and those may be approximated in some cases</li>
</ul>



<a name="191669429"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669429" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669429">(Mar 24 2020 at 20:41)</a>:</h4>
<p>Those all make sense</p>



<a name="191669541"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669541" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669541">(Mar 24 2020 at 20:42)</a>:</h4>
<p>I'm not sure if there are other bullet points to add but I think that's helpful in my mind for scoping out "things we don't plan to solve"</p>



<a name="191669552"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669552" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669552">(Mar 24 2020 at 20:42)</a>:</h4>
<p>and we can amend it as we go</p>



<a name="191669562"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669562" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669562">(Mar 24 2020 at 20:42)</a>:</h4>
<p>the immediate steps we know of then are :</p>



<a name="191669570"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669570" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669570">(Mar 24 2020 at 20:42)</a>:</h4>
<ul>
<li>modeling builtin traits</li>
</ul>



<a name="191669587"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669587" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669587">(Mar 24 2020 at 20:42)</a>:</h4>
<p>gonna work on that today</p>



<a name="191669612"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669612" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669612">(Mar 24 2020 at 20:42)</a>:</h4>
<p>after this I think</p>



<a name="191669614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669614">(Mar 24 2020 at 20:42)</a>:</h4>
<p>it seems like maybe fn and closure types are kind of "nice to have"</p>



<a name="191669625"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669625" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669625">(Mar 24 2020 at 20:42)</a>:</h4>
<p>there is some work on the chalk side of kind of growing our types to accomodate more things though</p>



<a name="191669666"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669666" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669666">(Mar 24 2020 at 20:43)</a>:</h4>
<p>Ah, so "const"</p>



<a name="191669684"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669684" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669684">(Mar 24 2020 at 20:43)</a>:</h4>
<p>ah yeah, that</p>



<a name="191669691"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669691" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669691">(Mar 24 2020 at 20:43)</a>:</h4>
<p>I feel like we can just sort of ignore const, but I think you were pointing out that may be hard, because it appears in some key impls?</p>



<a name="191669729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669729">(Mar 24 2020 at 20:43)</a>:</h4>
<p>So, whenever I see a const, I just substitute as an <code>()</code></p>



<a name="191669732"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669732" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669732">(Mar 24 2020 at 20:43)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669625" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669625">said</a>:</p>
<blockquote>
<p>there is some work on the chalk side of kind of growing our types to accomodate more things though</p>
</blockquote>
<p>I feel like maybe we should loop this separately, towards the <em>other</em> goal of aligning rustc and chalk types</p>



<a name="191669734"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669734" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669734">(Mar 24 2020 at 20:43)</a>:</h4>
<p>so yes, just ignoring it</p>



<a name="191669795"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669795" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669795">(Mar 24 2020 at 20:44)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669729" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669729">said</a>:</p>
<blockquote>
<p>So, whenever I see a const, I just substitute as an <code>()</code></p>
</blockquote>
<p>is this causing any immediate problems?</p>



<a name="191669829"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669829" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669829">(Mar 24 2020 at 20:44)</a>:</h4>
<p>if not, I'm <em>inclined</em> to say that's "ok" for now, though I suspect that doing some sort of const integration wouldn't be too hard, and it might be nic to at least have a goal of having some <em>conversations</em> about how to do it</p>



<a name="191669865"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669865" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669865">(Mar 24 2020 at 20:44)</a>:</h4>
<p>side note that I think this "sync up meeting" is generally working well but those kind of longer form conversations might also be nice to schedule at sprint time</p>



<a name="191669898"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669898" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669898">(Mar 24 2020 at 20:45)</a>:</h4>
<p>like "design work for sprint N+1"</p>



<a name="191669902"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669902" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669902">(Mar 24 2020 at 20:45)</a>:</h4>
<p>nope</p>



<a name="191669967"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191669967" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191669967">(Mar 24 2020 at 20:45)</a>:</h4>
<p>in fact, I don't even think I need that now that I'm <em>actually</em> limiting the set of matching impls by trait</p>



<a name="191670126"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670126" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670126">(Mar 24 2020 at 20:46)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669865" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191669865">said</a>:</p>
<blockquote>
<p>side note that I think this "sync up meeting" is generally working well but those kind of longer form conversations might also be nice to schedule at sprint time</p>
</blockquote>
<p>"sprint time" meaning what</p>



<a name="191670158"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670158" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670158">(Mar 24 2020 at 20:47)</a>:</h4>
<p>well .. now maybe :)</p>



<a name="191670185"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670185" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670185">(Mar 24 2020 at 20:47)</a>:</h4>
<p>depends if we want to use this slot of schedule a separate slot</p>



<a name="191670217"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670217" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670217">(Mar 24 2020 at 20:47)</a>:</h4>
<p>I'm basically just saying that I think "have a few conversations about const and hopefully sketch out a design for next time" is a good sprint goal, and it would be resolved by scheduling a time to chat in the next week or two</p>



<a name="191670303"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670303" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670303">(Mar 24 2020 at 20:48)</a>:</h4>
<p>oh</p>



<a name="191670328"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670328" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670328">(Mar 24 2020 at 20:48)</a>:</h4>
<p>I think that this time slot is probably fine for this?</p>



<a name="191670430"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670430" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670430">(Mar 24 2020 at 20:49)</a>:</h4>
<p>I mean, I know a lot of the time for the past few meetings has gone towards sprint planning and such, so maybe it's not so much "design meeting", more so "wg-traits meeting of design,planning,etc."</p>



<a name="191670762"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670762" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670762">(Mar 24 2020 at 20:52)</a>:</h4>
<p>we've been using it for differnt things</p>



<a name="191670779"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670779" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670779">(Mar 24 2020 at 20:52)</a>:</h4>
<p>but we have often done design work</p>



<a name="191670792"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670792" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670792">(Mar 24 2020 at 20:52)</a>:</h4>
<p>right</p>



<a name="191670796"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670796" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670796">(Mar 24 2020 at 20:52)</a>:</h4>
<p>anyway ok so I was editing the hackmd</p>



<a name="191670835"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670835" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670835">(Mar 24 2020 at 20:53)</a>:</h4>
<p>so, yes, I agree we should schedule a meeting during this sprint to flesh out const design :)</p>



<a name="191670915"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670915" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670915">(Mar 24 2020 at 20:53)</a>:</h4>
<p>take a look at <a href="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?edit" target="_blank" title="https://hackmd.io/nrhN5A8sR2eY9UdfJTKcJg?edit">the hackmd</a></p>



<a name="191670961"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670961" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670961">(Mar 24 2020 at 20:54)</a>:</h4>
<p>if you're not already</p>



<a name="191670983"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670983" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670983">(Mar 24 2020 at 20:54)</a>:</h4>
<p>yes</p>



<a name="191670989"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191670989" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191670989">(Mar 24 2020 at 20:54)</a>:</h4>
<p>I am</p>



<a name="191671324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671324">(Mar 24 2020 at 20:57)</a>:</h4>
<p>I elaborated out the builtin traits a bit</p>



<a name="191671337"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671337" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671337">(Mar 24 2020 at 20:57)</a>:</h4>
<p>I think that <code>Unsize</code> shoudl be out of scope</p>



<a name="191671359"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671359" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671359">(Mar 24 2020 at 20:57)</a>:</h4>
<p>that's used for coercions like <code>let x: &amp;dyn Debug = &22;</code></p>



<a name="191671374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671374">(Mar 24 2020 at 20:57)</a>:</h4>
<p>i.e., coercing from <code>&amp;i32</code> to <code>&amp;dyn Debug</code></p>



<a name="191671398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671398">(Mar 24 2020 at 20:57)</a>:</h4>
<p>or from <code>&amp;[T; N]</code> to <code>&amp;[T]</code></p>



<a name="191671410"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671410" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671410">(Mar 24 2020 at 20:58)</a>:</h4>
<p>the rules are kind of complex and I think better left for later</p>



<a name="191671459"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671459" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jane Lusby <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671459">(Mar 24 2020 at 20:58)</a>:</h4>
<p>ack</p>



<a name="191671463"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671463" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671463">(Mar 24 2020 at 20:58)</a>:</h4>
<p>I would put the <code>Fn</code> traits as a "reach goal"</p>



<a name="191671489"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671489" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671489">(Mar 24 2020 at 20:58)</a>:</h4>
<p>not <em>so</em> complex but will require us to add some new types for function-defs and closures and bit of other new stuff</p>



<a name="191671495"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671495" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671495">(Mar 24 2020 at 20:58)</a>:</h4>
<p>so not where I'd start</p>



<a name="191671550"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671550" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671550">(Mar 24 2020 at 20:59)</a>:</h4>
<p><span class="user-mention" data-user-id="232957">@Jack Huey</span> I feel like the list of work items is pretty incomplete in that it doesn't really include "land jack's branch"</p>



<a name="191671574"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671574" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671574">(Mar 24 2020 at 20:59)</a>:</h4>
<p>and I'm not 100% sure what's blocking or needed for that, but maybe you want to add some more specific things if you can think of em? It's ok to leave it kind of vague and just have it be assigned to you I think too</p>



<a name="191671699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671699">(Mar 24 2020 at 21:00)</a>:</h4>
<p>We'll have to see how it goes when I try to convert rustc types to Chalk types deeply and eagerly</p>



<a name="191671721"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671721" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671721">(Mar 24 2020 at 21:00)</a>:</h4>
<p>that's a clear item I guess</p>



<a name="191671748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671748">(Mar 24 2020 at 21:00)</a>:</h4>
<p>but assuming that "works", then I think my branch meets to MVP guidelines</p>



<a name="191671899"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671899" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671899">(Mar 24 2020 at 21:02)</a>:</h4>
<p>ok, well, we're at 1:01 hours</p>



<a name="191671936"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671936" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671936">(Mar 24 2020 at 21:02)</a>:</h4>
<p>True</p>



<a name="191671944"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671944" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671944">(Mar 24 2020 at 21:02)</a>:</h4>
<p>quickly</p>



<a name="191671959"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671959" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671959">(Mar 24 2020 at 21:02)</a>:</h4>
<p>what are your thoughts on this: <a href="#narrow/stream/144729-wg-traits/topic/.22skill.20tree.22/near/190652842" title="#narrow/stream/144729-wg-traits/topic/.22skill.20tree.22/near/190652842">https://rust-lang.zulipchat.com/#narrow/stream/144729-wg-traits/topic/.22skill.20tree.22/near/190652842</a></p>



<a name="191671962"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671962" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671962">(Mar 24 2020 at 21:02)</a>:</h4>
<p>( I have some secret goals, I wonder if they fit, or if I'm being overly ambitious. )</p>



<a name="191671979"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671979" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671979">(Mar 24 2020 at 21:03)</a>:</h4>
<p>(I want to hear about secret goals)</p>



<a name="191671999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191671999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191671999">(Mar 24 2020 at 21:03)</a>:</h4>
<p>Ah, hmm, I forgot about that comment</p>



<a name="191672032"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672032" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672032">(Mar 24 2020 at 21:03)</a>:</h4>
<p>It seems pretty easy for us to model "inherent associated types" if we have the whole alias mechanism truly working</p>



<a name="191672052"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672052" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672052">(Mar 24 2020 at 21:03)</a>:</h4>
<p>yes</p>



<a name="191672105"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672105" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672105">(Mar 24 2020 at 21:04)</a>:</h4>
<p>seems fine to add it as a goal</p>



<a name="191672117"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672117" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672117">(Mar 24 2020 at 21:04)</a>:</h4>
<p>let me jot it down...</p>



<a name="191672144"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672144" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672144">(Mar 24 2020 at 21:04)</a>:</h4>
<p>as far as secret goals, well, maybe before that, we didn't talk at all about recursive solver, ambig assoc. types,  etc</p>



<a name="191672164"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672164" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672164">(Mar 24 2020 at 21:04)</a>:</h4>
<p>Right those</p>



<a name="191672218"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672218" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672218">(Mar 24 2020 at 21:05)</a>:</h4>
<p>I didn't mention these because it's not clear how they "fit" into everything</p>



<a name="191672223"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672223" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672223">(Mar 24 2020 at 21:05)</a>:</h4>
<p>if that makes sense</p>



<a name="191672268"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672268" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672268">(Mar 24 2020 at 21:05)</a>:</h4>
<p>like, they are definitely things to work on, but they are somewhat still in the realm of "trying to work out design"</p>



<a name="191672345"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672345" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672345">(Mar 24 2020 at 21:06)</a>:</h4>
<p>yeah, I just think we should mention it</p>



<a name="191672364"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672364" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672364">(Mar 24 2020 at 21:06)</a>:</h4>
<p>similarly to opaque types</p>



<a name="191672385"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672385" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672385">(Mar 24 2020 at 21:06)</a>:</h4>
<p>hmm maybe I'll "treat myself" to finally exploring <span class="user-mention" data-user-id="129457">@Florian Diebold</span>'s branch today</p>



<a name="191672422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672422">(Mar 24 2020 at 21:07)</a>:</h4>
<p>I have like 40-50 minutes before I stop working and since I never got around to making my to do list today I'm not skipping anything else ;)</p>



<a name="191672433"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672433" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672433">(Mar 24 2020 at 21:07)</a>:</h4>
<p>anyway, my secret goals are in some way similar</p>



<a name="191672453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672453">(Mar 24 2020 at 21:07)</a>:</h4>
<p>exploratory I mean</p>



<a name="191672456"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672456" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672456">(Mar 24 2020 at 21:07)</a>:</h4>
<p>there are two</p>



<a name="191672484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672484">(Mar 24 2020 at 21:08)</a>:</h4>
<p>one of them is that on rustc we need to complete some work on "removing the leak check" that I began -- or at least take the next step</p>



<a name="191672523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672523">(Mar 24 2020 at 21:08)</a>:</h4>
<p>I'm honestly not sure if I can mentor that or it's just a work item for me</p>



<a name="191672538"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672538" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672538">(Mar 24 2020 at 21:08)</a>:</h4>
<p>but it's imporant to helping rustc move towards lazy norm</p>



<a name="191672543"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672543" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672543">(Mar 24 2020 at 21:08)</a>:</h4>
<p>so I want to put some time into it</p>



<a name="191672591"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672591" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672591">(Mar 24 2020 at 21:08)</a>:</h4>
<p>the other which is more chalk related is doing the work I wanted to do to explore a new strategy for region integration, one where chalk has a more active role in solving constraints</p>



<a name="191672636"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672636" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672636">(Mar 24 2020 at 21:09)</a>:</h4>
<p>I remember now that the main "next step" I was trying to do there was to do remove "semantic equality" in favor of "syntactic equality", as we've talked about for some time</p>



<a name="191672642"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672642" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672642">(Mar 24 2020 at 21:09)</a>:</h4>
<p>and that was <em>fairly close</em></p>



<a name="191672661"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672661" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672661">(Mar 24 2020 at 21:09)</a>:</h4>
<p><span class="user-mention silent" data-user-id="116009">nikomatsakis</span> <a href="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191672636" title="#narrow/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24/near/191672636">said</a>:</p>
<blockquote>
<p>I remember now that the main "next step" I was trying to do there was to do remove "semantic equality" in favor of "syntactic equality", as we've talked about for some time</p>
</blockquote>
<p>(is it at all clear what I mean by this?)</p>



<a name="191672673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672673">(Mar 24 2020 at 21:09)</a>:</h4>
<p>I definitely think adding the removing leak check goal isn't a bad idea, I just don't know who else would work on it</p>



<a name="191672695"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672695" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672695">(Mar 24 2020 at 21:09)</a>:</h4>
<p>well, it's maybe good in trying to keep me honest, and I really do think we need to make progress on it</p>



<a name="191672744"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672744" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672744">(Mar 24 2020 at 21:10)</a>:</h4>
<p>syntactic equality also goes along the lines of "working through design"</p>



<a name="191672787"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672787" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672787">(Mar 24 2020 at 21:10)</a>:</h4>
<p>indeed</p>



<a name="191672898"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672898" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672898">(Mar 24 2020 at 21:11)</a>:</h4>
<p>I think we can probably just remove "increase chalk perf" as a goal this time?</p>



<a name="191672912"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672912" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672912">(Mar 24 2020 at 21:11)</a>:</h4>
<p>though I remain super excited about the idea of extracting a <code>.chalk</code> file</p>



<a name="191672918"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672918" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672918">(Mar 24 2020 at 21:11)</a>:</h4>
<p>well</p>



<a name="191672927"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672927" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672927">(Mar 24 2020 at 21:12)</a>:</h4>
<p>so I put this there</p>



<a name="191672990"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191672990" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191672990">(Mar 24 2020 at 21:12)</a>:</h4>
<p>because I'm trying to think about some Chalk-only things to work on</p>



<a name="191673002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673002">(Mar 24 2020 at 21:12)</a>:</h4>
<p>for people that are interested in getting involved</p>



<a name="191673097"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673097" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673097">(Mar 24 2020 at 21:13)</a>:</h4>
<p>Another piece in there was adding the <code>Visit</code> trait, but that is less of a Goal and more of just a "good first issue"</p>



<a name="191673119"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673119" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673119">(Mar 24 2020 at 21:13)</a>:</h4>
<p>(I see you <span class="user-mention" data-user-id="251766">@Areredify</span> )</p>



<a name="191673123"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673123" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673123">(Mar 24 2020 at 21:13)</a>:</h4>
<p>yeah I think that fits into the "align rustc and chalk" goal</p>



<a name="191673126"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673126" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673126">(Mar 24 2020 at 21:13)</a>:</h4>
<p>I was going to add it there</p>



<a name="191673138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191673138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191673138">(Mar 24 2020 at 21:13)</a>:</h4>
<p>and it would be really nice to have :)</p>



<a name="191675009"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191675009" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191675009">(Mar 24 2020 at 21:28)</a>:</h4>
<p>Can you attach the link(s) where you talked about region semantic/syntactic equality? I would like to read about that, if possible</p>



<a name="191676142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/design%20meeting%202020.03.24/near/191676142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/design.20meeting.202020.2E03.2E24.html#191676142">(Mar 24 2020 at 21:39)</a>:</h4>
<p><span class="user-mention" data-user-id="251766">@Areredify</span> <a href="https://github.com/rust-lang/wg-traits/blob/master/minutes/design-2019-10-16.md" target="_blank" title="https://github.com/rust-lang/wg-traits/blob/master/minutes/design-2019-10-16.md">this conversation</a> discussed sem vs syn equality</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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